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Publications (170)
Despite the widely acknowledged role of the anthropogenic drivers of climate change, there has been little success in developing a clear overview of the strengths and weaknesses of counter-measures or developing a consensus on their application. Problems with conventional approaches arise from the strongly coupled, multidisciplinary issues involved...
The impacts of the current COVID-19 pandemic illustrate the global-level sensitivity to such threats. As understanding of major hazards is generally based on past experience and there is a lack of good historical precedents, approaches and models currently employed to assess risks and guide responses generally lack transparency and are often associ...
https://content.yudu.com/web/442ay/0A444i1/NEI0321-Pros/html/index.html?page=16&origin=reader
An important property of locations selected to host deep geological repositories for higher level radioactive wastes is their capacity to retard the movement of any radionuclides released from engineered barriers. Site characterization cannot measure this characteristic directly and hence models form the essential link between field observations an...
Global warming is a major threat that justifies all practical measures to decrease greenhouse gas emissions, but also an assessment of options to minimise the consequences of environmental change. What might this mean for nuclear waste disposal?
https://www.neimagazine.com/features/featurenuclear-waste-management-in-a-warming-world-8205862/
The Japanese geological disposal programme for radioactive waste is based on a volunteering approach to siting, which places particular emphasis on the need for public acceptance. This, as established in law, emphasises the development of a repository project as a partnership with local communities and involves stakeholders in important decisions a...
Since the Fukushima reactor meltdowns, there has been increased public concern in Japan regarding nuclear issues and also on the potential of major natural hazards to cause accidents at nuclear facilities. In response to this-and to help rebuild the public confidence required to site a repository-studies have examined how the concept of resilience,...
The loss of core cooling for units 1–3 during the accident at Fukushima Dai-ichi caused major fuel damage. Although full details are not yet available, fuel melting produced corium within the reactor pressure vessels that has, to an unknown degree, melted through into the primary containment. The present priority is cooling the damaged reactors and...
Robust disposal modules, or compact, highly engineered caverns could offer a more resilient alternative for disposal of spent nuclear fuel.
The geological disposal of radioactive wastes is generally accepted to be the most practicable approach to handling the waste inventory built up from over 70 years accumulation of power production, research-medical-industrial and military wastes. Here, a brief overview of the approach to geological disposal is presented along with some information...
Natural analogues have been previously used to support the safety case for direct disposal of spent nuclear fuel, but the focus of such work was very dependent on the key barriers of specific national disposal concepts. Investigations of the feasibility of such disposal in Japan are at an early stage but, nevertheless, it is clear that building a r...
In the wake of the Great Tohoku earthquake and tsunami, which resulted in significant damage to the Fukushima Daiichi nuclear power plant, considerable radioactive discharge and deposition occurred. Populations were evacuated from the zones that received the most deposition and overarching “Special Measures” laws established the Ministry of the Env...
In the wake of the Great Tohoku earthquake and tsunami, which resulted in significant damage to the Fukushima Daiichi nuclear power plant, considerable radioactive discharge and deposition occurred. Populations were evacuated from the zones that received the most deposition and overarching “Special Measures” laws established the Ministry of the Env...
This report provides a concise overview of knowledge and experience gained from the activities for environmental remediation after the Fukushima Daiichi (1F) accident. It is specifically tailored for international use, to establish or refine the technical basis for strategic, off-site response to nuclear incidents. It reflects JAEA’s key role in th...
Recovery from the core melts at Fukushima Dai-ichi will involve a major program of work that will run over decades and pose a number of challenges for the large number of Japanese and international radiochemists who will be involved. Apart from improved techniques to monitor and clean up contamination off-site, concepts for effective management of...
The project “Developing a CCS communication framework for Japan” aims to test a prototype Knowledge Management System (KMS) on a pilot scale, with a view to more broadly utilizing the methodology in an international context. For this purpose, an on-line community was formed, involving CCS experts (10 to 15) from major Japanese CCS-related organizat...
The CAvern REtrievable (CARE) concept was originally developed to provide flexibility in tailoring disposal of vitrified HLW to small volunteer host sites, where high emplacement density leads to significant challenges in terms of the management of radiogenic heat. Including an extended storage period in underground caverns prior to sealing solved...
With the past Government policy of 100% reprocessing in Japan now open to discussion, options for direct disposal of spent fuel (SF) are now being considered in Japan. The need to move rapidly ahead in developing spent fuel management concepts is closely related to the ongoing debate on the future of nuclear power in Japan and the desire to underst...
The 2011 accident at the Fukushima Dai-ichi Nuclear Power Plant, Japan, released large quantities of volatile radionuclides, requiring evacuation of a 20 km zone around the reactor site plus additional areas where fallout was particularly high. After decay of shorter-lived isotopes, off-site contamination is now dominated by (134/137)Cs, with ∼1800...
Two devastating tsunamis in the 21st century were caused by large megathrust earthquakes on tectonic plate boundaries; the Boxing Day tsunami in 2004 and the Great Tohoku tsunami in 2011. Both of these events have led to a focus on tsunamis caused by megathrusts when assessing risks to coastal nuclear power plants. From a longer time perspective, h...
The regional contamination from radiation released from Fukushima Dai-ichi has decreased considerably since the accident – due to radioactive decay and the natural self-cleaning of environmental systems. Despite the generally low health hazard involved, there has been great investment in developing and testing technology for remediation. This will...
The Great Tohoku earthquake and tsunami caused regional devastation and great loss of life, but media coverage in Japan – and even more so in the rest of the world – has focused predominantly on the meltdowns at Fukushima Dai-ichi and associated radiation release. Even 18 months after the incident, its ramifications for the future development of nu...
Since the early years of deep geological disposal programmes Underground Rock Laboratories (URLs) have been key components of national programmes. The strategic roles of URLs and the advantages of gaining practical experience through underground testing can be traced back to the earliest waste management initiatives in the 1960s and 1970s. Many nat...
We have examined a number of hyperalkaline (pH 9-12) springs situated in
ophiolites in various locations in the Philippines (Pangasinan,
Zambales, Palawan). These clearly result from interactions of
groundwater with mafic minerals, but differences in major- and
trace-element compositions suggest complex reactions that need further
study. Such sprin...
Concepts for the disposal of high-level radioactive waste (HLW) and spent fuel (SF) in several countries include a massive steel overpack within a bentonite buffer. In past conservative safety assessments to demonstrate feasibility of geological disposal, overpacks are assumed to provide complete containment for a given lifetime, after which all fa...
Several national programs for geological disposal of higher activity radioactive waste will initiate siting via a call for volunteers. This is probably furthest advanced in Japan (NUMO) and the UK (NDA RWMD). In both these cases, rather than focusing on a reference repository concept, a catalogue of options has been developed. This requires a proce...
The Great Tohoku earthquake and tsunami caused regional devastation and great loss of life, but media coverage in Japan – and even more so in the rest of the world – has focused predominantly on the meltdowns at Fukushima Dai-ichi and associated radiation release. Even 18 months after the incident, its ramifications for the future development of nu...
The success of carbon capture and storage (CCS) projects depends on the ability of storage sites to contain CO2 without leakage; and the ability to convince regulators and the general public in the safety of the technology. If leakage were to occur after formal closure of the injection site, this could be over small areas from discrete point source...
A viable CCS project depends on effective implementation and confidence in long-term confinement; not only supported by technical specialists in implementing and regulatory organisations, but also by the wider scientific community, political decision makers and the general public. However, sharing knowledge between, and building confidence in, indi...
Tsunami has the ability to impact a variety of nuclear facilities in different geographical settings and the risk is wider in the nuclear reactors in coastal areas. The impact of a tsunami of particular size is influenced by the source of the water displacement, particularly if it is a major earthquake and/or volcanic eruption relatively nearby. Ma...
Geological disposal of radioactive waste epitomises many of the greatest challenges in Knowledge Management (KM): collating and synthesising knowledge from a host of diverse disciplines with exponentially expanding information bases, developing and preserving tacit knowledge in a project implemented over more than a century, rigorously assuring qua...
In Japan, uplift/erosion scenarios must be analysed even if they occur far in the future, as no assessment cut-off times have yet been defined. For this purpose, the geological record of river terrace formation and their long-term evolution have been studied further, with the aim of constructing a better defined fluvial erosion model than the origi...
The exponential growth in the knowledge base for radioactive waste management is a cause for concern in many national programmes. In Japan, this problem is exacerbated by a volunteering approach to siting of a deep geological repository, which requires particular flexibility in the tailoring of site characterisation plans, repository concepts and a...
The repository concepts developed by PNC and Nagra for the disposal of vitrified high-level waste show many common features; both concepts involve deep geological disposal, with massive engineered barriers of similar design. PNC and Nagra have recently published comprehensive performance assessments based on their repository concepts and these are...
Over the past 20 years, radioactive waste microbiology has included a variety of analyses of disposal options for High Level (HLW) and Low/Intermediate Level (L/ILW) waste. Projects have covered a wide range of areas including: fundamental microbiology of geological formations; microbial tolerance to extreme conditions; biodegradation of repository...
The long-term programme of in-situ radionuclide migration experiments in the underground test site at Grimsel (GTS) involves the development and testing of radionuclide transport models with their associated databases. The field experiments are carried out in a water-bearing shear zone in crystalline rock utilising a suite of tracers of differing g...
A volunteering approach to siting in Japan imposes novel challenges to performance assessment that can only be addressed by rethinking the entire methodology and toolkit developed over the last 3 decades. The move from demonstrated conservatism to much more realistic assessment requires much more sophisticated development of scenarios and more powe...
The early ’80s UK programme for deep geological disposal of high-level radioactive waste was advanced and at the stage of characterising potential sites. When this project was put on hold in the mid ’80s, much expertise in this field was lost. In Japan R&D in the ’80s resulted in major generic safety assessments to demonstrate feasibility in the ’9...
The diverse range of long-lived radioactive wastes without significant heat output specified for deep geological disposal (here termed TRU) pose challenges that are potentially more serious than those from vitrified high-level waste and spent fuel. Despite this, the latter tend to be the focus of R&D in national programmes. Such challenges are part...
Earth is a dynamic planet and all points on the land surface are subject to processes that cause either uplift or subsidence. These types of vertical movements can vary considerably in magnitude and can occur on a wide range of timescales. Short-term cyclic motions, caused by planetary orbits, range from minute daily movements due to gravitational...
A large number of nuclear facilities are situated directly on or very close to the coast. This is not coincidental. Such locations ease the transportation of bulky or sensitive materials by ship and offer an effectively limitless supply of cooling water. Nuclear facilities may also be less intrusive in coastal settings. For some countries there may...
In preparation for actual repository implementation, designs that could be tailored to specific sites need to be considered. This requires a paradigm shift in design philosophy, moving away from a single reference design towards a flexible and systematic “catalogue” of engineered barrier components and associated repository infrastructure. To suppo...
Most designs of disposal facilities for higher toxicity radioactive wastes were developed for generic feasibility assessment and hence tend to be rather simple in terms of layout and conservative in the choice of engineered barrier materials. Recently, there has been a trend to reassess such designs in the light of moves towards implementation, whe...
In Japan, uplift/erosion scenarios must be analysed even if they occur far in the future, as no assessment cut-off times have yet been defined. For this purpose, an argumentation method is developed to allow sensible scenarios to be constructed. The consequences of erosion of the repository may be better estimated in terms of radionuclide fluxes an...
The volunteer siting of disposal facilities for vitrified high-level radioactive waste (HLW) and TRU waste in Japan results in a particular need for flexibility to allow repositories to be tailored to specific sites. Instead of a single reference concept, a “catalogue” of designs for individual repository components is being developed, which can th...
Recognising the benefits to be gained by integrating national and international experience into a rapidly growing programme, NUMO already in June 2001 set up both domestic and international technical advisory committees. These groups supported NUMO during the time when many of the basic, often innovative, concepts that characterise the Japanese dee...
The characterisation of potential repository sites will produce huge volumes of information, which must be correlated, quality assured, integrated, analysed, documented and archived in a rigorous and efficient manner. While some of this work involves rather routine data handling that may be easily automated, much of it requires input of tacit knowl...
A detailed assessment of studies of oxidising redox fronts around fractures at depth in otherwise “reducing” environments suggests that the usual explanation, in terms of past disturbances that have resulted in deep penetration of oxidising water, are incompatible with hydrogeological and/or geochemical observations. An alternative hypothesis, micr...
The Knowledge Management System by Japan Atomic Energy Agency (JAEA KMS) is being developed to be flexible and able to respond to potential changes of boundary conditions. On a shorter timescale, the KMS must encourage flexibility in the methodology used for carrying out and presenting performance assessments. This is closely linked to development...
The safety case, as defined in Japan, is an integrated set of arguments to show that a repository is sufficiently safe during both operational and post-closure phases. It explicitly includes the findings of a safety assessment and a demonstration of confidence in these findings. It is developed in a stepwise manner, with provisional cases used to s...
Over the last few years, a major national programme of public consultation has been under way in the UK resulting, in 2006, in the announcement by government of geological disposal as the most appropriate solution for the long-term management of the UK’s long-lived and higher-activity radioactive waste and the launch, in 2008, of an implementation...
The exponential growth in the knowledge base for radioactive waste management is a cause for concern in many national programmes. In Japan, this problem is exacerbated by a volunteering approach to siting of a deep geological repository, which requires particular flexibility in the tailoring of site characterisation plans, repository concepts and a...
Comprehensive total system performance assessment (PA) is a key component of the safety case. Within this PA there are a number of tasks that reuse specific models and datasets, together with associated knowledge base for the disposal system considered. These are tasks where recent developments in the Knowledge Management System by Japan Atomic Ene...
Key words: bentonite/hyperalkaline cement leachate interaction, low alkali cement, natural analogue 1. Introduction Bentonite is one of the most safety-critical components of the engineered barrier system in the disposal concepts developed for many types of radioactive waste. The choice of bentonite results from its favourable properties (including...
Bentonite plays a significant barrier role in many radioactive waste repository designs, where it has been chosen due to its favourable properties such as plasticity, swelling capacity, colloid filtration, low hydraulic conductivity and its stability in relevant geological environments. However, bentonite is unstable at high pH meaning that it coul...
Available from http://nora.nerc.ac.uk/5678/1/OR08076.pdf
Many current concepts for the engineered barriers of high-level waste repositories include a bentonite buffer or backfill which will be exposed to significantly raised temperatures for a period of decades to centuries. To assess its stability, available experimental and natural analogue data on thermally-exposed bentonite is reviewed. The two main...
This chapter discusses the development of geological disposal concepts. It provides an introduction to the historical evolution of disposal of radioactive wastes and a consideration of the range of options available. The chapter provides a short overview on the alternatives to geological disposal (section 3.4), which are classed as politically bloc...
This chapter discusses the recent trends in repository implementation in national (and international) repository programs, followed by a look at where the main priorities for future efforts might usefully be directed. It is clear that radwaste disposal can only become widely accepted when there is a more broad-based acceptance by all stakeholders o...
The information explosion resulting from modern technology is identified as a critical problem for deep geological disposal of high-level radioactive waste (HLW). A paradigm shift is needed in the basic concept for information management. This recognition had led to the development of a 'next generation' Knowledge Management System (the JAEA KMS) t...
The priorities for focusing R&D in the nuclear waste management field can be determined by considering the way in which global and national boundary conditions are likely to evolve during this century. Some of the R&D goals are clearly achievable based on current technology. Others will require novel developments and hence are inherently more diffi...
Geochemical exploration commonly utilises observations from nature to help find, and explain the genesis of, anomalies such as ore bodies. Radioactive waste disposal involves the inverse process of using such expertise to design a geochemical anomaly (the repository) which will persist for geological timescales. The particular challenge is developi...
The recently developed Cavern Extended Storage (CES) repository design for radioactive waste combines some of the advantages of the flexibility provided by long-term interim storage with the safety of deep geological disposal. It is also of particular interest where demands are made for long periods of institutional control and monitoring (or stage...
During 20 years of operation, Nagra's Grimsel underground research facility has seen a continuous evolution in the type and scale of work carried out. The focus on geological characterisation technology development in the '80s was followed by more emphasis on performance assessment model testing and studies of engineered barrier systems in the '90s...
The work of the Grimsel Test Site (GTS), regarding the radoactive waste disposal programmes is described. Apart from technical work carried out at this location, GTS serves as a focus for public information activities for regional, national and international visitors. GTS performs examination, development and testing of characterization technologie...
The disposal of long-lived radioactive waste by using the cavern retrievable (CARE) method is discussed. The repository in the CARE method is implemented in two distinct stages and ventilated underground caverns are operated like a surface storage facility, with waste being fully accessible. When a decision is made to close the repository, the cave...
It is now commonly recognised that public acceptance is one of the key factors influencing the feasibility of nuclear waste repositories – or indeed, any major industrial or technical developments. The general antipathy against anything ''radioactive'' is further compounded by the difficulty of developing a simple, transparent safety case for a fac...
NUMO’s decision to call for volunteers to host a Japanese HLW repository provides special challenges for repository design. With emphasis placed on public acceptance, a range of alternative designs is needed which can be tailored to sites meeting the critical geological stability criteria.
In the past, safety assessments for deep geological repositories have tended to focus on the post-closure phase. Increasingly, focus is now moving onto the operational phase, which is particularly associated with the reliability of remote-handling technology in a challenging environment.
This chapter presents a case study from the field of radioactive waste disposal. The chapter provides a short introduction to modeling the distribution of radionuclides in the geological environment (or geosphere). The basic principles of radionuclide geosphere transport modeling are examined, with the emphasis on identifying the processes and stru...
Environmental Radiochemical Analysis II brings together comprehensive, up-to-date information from international experts in the field. Coverage includes information on new methods of radionuclide analyses, developments and improvements in existing methods, method comparisons, gamma detector performance and new software products, method uncertainty,...
One of the key arguments for deep geological disposal of radioactive waste is that, even in the event that barriers fail in the far future, the surrounding rock will greatly limit any subsequent release of radionuclides. Understanding of this barrier function has improved considerably over the last couple of decades based on an integrated programme...
As progress is slowly made towards siting and constructing repositories for high-level radioactive waste (HLW), interest is growing in moving from established, rather idealised designs towards concepts which are better into the geological conditions of specific sites. Although long-term safety remains the key goal, more emphasis is now placed on op...
Fundamentals of Radioactive Waste Disposal
This chapter provides a short introduction to modelling the distribution of radionuclides in the geological environment (or geosphere). The chapter begins with the basic principles of radionuclide geosphere transport modelling are examined, with the emphasis on identifying the processes and structures of relevance to contaminant transport. Approach...
The search for greater public acceptance for radioactive waste disposal has meant that repository planning increasingly includes monitoring, institutional control and flexibility with respect to retrieval and reversability. However, the fundamental repository designs are generally unchanged. This paper describes an alternative – the Cavern Extended...
This chapter discusses the potential influence of microbial activity on repositories for radioactive waste. It provides a summary of general radioactive waste concepts and gives a brief account of the microbiology of host rocks and the repository environment. The significance of microbial activity on the various materials present in the repository...
The Grimsel Test Site, which has been in operation since 1984, is known in the radioactive waste management community for the scope and quality of the experiments and projects performed over the last two decades. This paper will overview Nagra's commitments and the current plans for future activities in association with Grimsel, which are being dev...
Most national high-level waste (HLW) disposal programs actually reflect, or are based on, concepts which were developed during the '70s or early '80s. Although suitable for demonstration of concept feasibility, designs of the engineered barrier system (EBS) do not take into account the tremendous developments in system understanding and materials t...
During 17 years of cooperation, the Grimsel underground test site in the Swiss Alps has become established as a major center for study of the deep geological environment. The present Phase V of operation involves collaboration of 15 organizations from 9 countries.
The 7 major projects currently running can be divided into 3 areas:
- Confirmation of...